Vascular Plants of North Carolina
Section: Common Name: Scientific Name: Family:
Account for Carolina October-flower - Polygonella croomii   Chapman
Members of Polygonaceae:
Members of Polygonella with account distribution info or public map:
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Section 6 » Family Polygonaceae
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AuthorChapman
DistributionWeakley (2018) and a few other references have pulled this taxon out of P. polygama as a valid species; many herbaria specimens of "P. polygama" thus have not been re-examined for which taxon is now involved. Even so, the map below is likely reasonably accurate. Southern Coastal Plain and Sandhills (where uncommon and local). Ranges north to southern Johnston County and west to Moore County.

A rather small range -- Coastal Plain of NC, SC, and GA.
AbundanceFrequent to common in regions with Carolina bays, but scarce or uncommon elsewhere. Plants are often abundant on bay sandrims. The NCNHP and NatureServe do not recognize this taxon, listing P. polygama only. The website editors suggest a State Rank of S3S4 (if not even S4). The Global Rank would probably be G4 if not G5.
HabitatXeric sandrims of Carolina bays, openings in xeric Longleaf Pine-Turkey Oak sandhills, other sand ridges. Typically in deep sands, often in Sand Barren habitat.
PhenologyFlowering and fruiting late August-November. Stem leaves have often or usually dropped by summer, leaving only small leaves on the branches.
IdentificationCarolina October-flower has suffruticose (semi-woody) stems that form masses of low "shrubs" 1-2 feet tall with straggly branches, and is quite showy when in flower. Above-ground portions become skeletons over the winter. The stems are woody, unlike our other jointweeds except for P. polygama. P. croomii can almost always be distinguished from the very similar P. polygama by leaf shape and size; this species has linear to linear-spatulate leaves about 4-13 mm long and 0.5-1.2 mm wide; P. polygama has wider leaves that are spatulate to linear-spatulate in shape, 7-30 mm long and 1-6 mm wide. See Weakley (2018) for additional characters, most of which are microscopic. Male plants have white corollas; females yellow-green.
Taxonomic CommentsWork by Richard LeBlond has shown that croomii can almost always be distinguished from polygama and that they have distinct ranges.

A few recent authors have noted the genetic similarity of Polygonella to Polygonum and have lumped the two. Because the two can be easily told apart in the field, taxon editors, including Weakley (2018), prefer to recognize both genera. As mentioned above, the NCNHP uses the name of Polygonum pinicola.
Other Common Name(s)None. October-flower is the name used for the combined two species.
State Rank[S3S4]
Global RankGNR
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photographercommentsphoto_linkcountyobsType
B.A. SorrieSame data. CumberlandPhoto_natural
B.A. SorrieXeric sandrim/roadside, Sept 2002. CumberlandPhoto_natural
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